Although significant progress has been made in reducing smoking prevalence in the US, the CDC reports that an estimated 43.8 million people, or 19.0 percent of all adults (18 years of age or older), smoke cigarettes (CDC, 2012). Cigarette smoking is the leading cause of preventable death in the US, accounting for more than 440,000 deaths, or one of every five deaths, each year (CDC, 2008). Although behavioral smoking cessation interventions appear to be equally as efficacious as pharmacologic interventions, behavioral interventions have limited availability and are not as easily disseminated. Innovative strategies are needed to make behavioral interventions more readily available and more easily disseminated. In the last decade, there has been increasing interest in mindfulness-based therapies across a wide range of health conditions and chronic diseases (Kabat-Zinn, 2013). Mindfulness-based treatment approaches have been extended to smoking cessation and a number of studies have demonstrated very promising outcomes. Smartphone technology offers new possibilities for the development of novel smoking cessation treatments delivered to smokers through a new, interactive medium. Acceptability of mobile health (mHealth) interventions is also very high and the prevalence of Smartphones has been rapidly increasing over the past few years across all socio- economic demographics including lower SES populations (Plaza et al, 2013). Additionally, mHealth interventions are able to deliver program content to users at their convenience and with greater privacy. The development of a mobile mindfulness-based smoking cessation program has the potential to overcome many of the limitations of group-taught mindfulness-based interventions including program variability, instructor style, and scheduling obstacles for study participants including the high time commitment to attend weekly sessions. We propose to develop Mobile Mindfulness-Based Smoking Cessation (MMBSC), a mindfulness-based smoking cessation program, delivered to smokers on their Smartphone devices (Android/iPhone). This program will be based on the Mindfulness-Based Stress Reduction (MBSR) program (Kabat-Zinn, 2013) tailored for smoking cessation.